scholarly journals Method comparison of three serum free light chain assays on the Roche Cobas 6000 c501 chemistry analyzer

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Dieuwertje Augustijn ◽  
Joannes F. M. Jacobs ◽  
Henk Russcher
Keyword(s):  
Method Comparison ◽  
Therapy Response ◽  
Reference Intervals ◽  
Light Chains ◽  
Reference Ranges ◽  
Free Light Chains ◽  
Monoclonal Gammopathies ◽  
Serum Free Light Chain ◽  
Roche Diagnostics ◽  
Roche Cobas

Abstract Objectives Free light chains (FLC) are important in the diagnosis, prognosis and monitoring of therapy response of patients with monoclonal gammopathies. In this study, we performed a method comparison of three FLC assays on the Cobas 6000 c501 chemistry analyzer of Roche Diagnostics. Methods Samples of 119 patients with various monoclonal gammopathies and 26 control patients were measured with the Freelite (The Binding Site), Diazyme (Diazyme Laboratories) and KLoneus (Trimero Diagnostics) FLC assays. A method comparison was performed and reference intervals of the three assays were validated. Results The analysis of the Bland-Altman agreement showed bias between the three FLC assays, ranging from −62.7 to 5.1% for κFLC and between −29.2 to 80.5% for λFLC. The Freelite and Diazyme assays have the highest agreement. The concordance of the FLC-ratio ranges from 41 to 75%, with the highest concordance between the Freelite and KLoneus assays. The FLC-ratio in 25 sera from healthy controls were within the reference ranges of the Freelite and KLoneus assays. The FLC-ratio was elevated in all 25 samples tested with the Diazyme assay. Conclusions The agreement for the free light chains is highest between the Freelite and the Diazyme assay and fair for the KLoneus assay. However, concordance of the FLC-ratio is highest when the Freelite and KLoneus assays were compared. Our data suggest that concordance for the Diazyme assay could be improved by recalibration. Because of absolute differences between the three methods in individual patients, none of the three FLC assays can be used interchangeably.

scholarly journals In-house age-specific reference ranges for free light chains measured on the SPAPlus® analyser

2020 ◽  
Vol 57 (2) ◽  
pp. 138-143
Author(s):  
Lauren Campbell ◽  
Dawn Simpson ◽  
Adrian Shields ◽  
Berne Ferry ◽  
Karthik Ramasamy ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Light Chain ◽  
Filtration Rate ◽  
Estimated Glomerular Filtration Rate ◽  
Free Light Chain ◽  
Light Chains ◽  
Reference Ranges ◽  
Free Light Chains ◽  
Serum Free ◽  
Serum Free Light Chain

Background The measurement of monoclonal free light chains is being increasingly utilized since the introduction of serum-based assays. It is important for laboratories to determine their own reference ranges in order to reflect the local population. The aim of this study was to determine if age-adjusted reference ranges for serum free light chains would have implications for demand management of further laboratory investigations including immunofixation. Methods After certain exclusions, 4293 samples from individuals seen in primary care across Oxfordshire between 2014 and 2016 were identified for analysis of patient characteristics, serum free light chain results and estimated glomerular filtration rate. Results We found age to be an independent variable when considering serum free light chain concentrations, ratio and estimated glomerular filtration rate. The reference ranges derived from our data differ markedly from the original Binding Site ranges. When the age-specific ranges are retrospectively applied to our population, there is a 38% decrease in follow-up testing with no loss of specificity. Conclusion We feel confident implementing new age-specific serum free light chain reference ranges in our laboratory. We have developed a simple algorithm for evaluating serum free light chains based on age and estimated glomerular filtration rate. We encourage laboratories to establish their own local reference ranges using large cohorts and their chosen serum free light chain assay platform.

scholarly journals Development of a rapid and quantitative lateral flow assay for the simultaneous measurement of serum κ and λ immunoglobulin free light chains (FLC): inception of a new near-patient FLC screening tool

2017 ◽  
Vol 55 (3) ◽  
Author(s):  
John P. Campbell ◽  
Jennifer L.J. Heaney ◽  
Meena Shemar ◽  
Dene Baldwin ◽  
Ann E. Griffin ◽  
...  
Keyword(s):  
Competitive Inhibition ◽  
Therapy Response ◽  
Lateral Flow ◽  
Light Chains ◽  
Reference Ranges ◽  
Free Light Chains ◽  
Hook Effect ◽  
Flow Test ◽  
Plasma Cell Dyscrasias ◽  
Lateral Flow Test

AbstractBackground:Serum free light chains (FLC) are sensitive biomarkers used for the diagnosis and management of plasma cell dyscrasias, such as multiple myeloma (MM), and are central to clinical screening algorithms and therapy response criteria. We have developed a portable, near-patient, lateral-flow test (SeraliteMethods:Assay interference, imprecision, lot-to-lot variability, linearity, and the utility of a competitive-inhibition design for the elimination of antigen-excess (‘hook effect’) were assessed. Reference ranges were calculated from 91 healthy donor sera. Preliminary clinical validation was conducted by retrospective analysis of sera from 329 patients. Quantitative and diagnostic results were compared to FreeliteResults:SeraliteConclusions:Seralite

Verification of serum reference intervals for free light chains in a local South African population

2013 ◽  
Vol 66 (11) ◽  
pp. 992-995
Author(s):  
Annalise E Zemlin ◽  
Megan A Rensburg ◽  
Hayley Ipp ◽  
Jurie J Germishuys ◽  
Rajiv T Erasmus
Keyword(s):  
Serum Protein ◽  
Light Chain ◽  
Reference Interval ◽  
Reference Intervals ◽  
Free Light Chain ◽  
Light Chains ◽  
Free Light Chains ◽  
Serum Free ◽  
Serum Free Light Chain ◽  
Normal Limits

Monoclonal serum free light chain measurements are used to follow up and manage patients with monoclonal gammopathies, and abnormal serum free light chain ratios are associated with risk of progression in certain diseases. We aimed to validate the reference intervals in our population. Reference intervals for κ and λ free light chains were established on 120 healthy adults. Creatinine levels were measured to exclude renal dysfunction and serum protein electrophoresis was performed. All creatinine values were within normal limits. After exclusion of subjects with abnormal serum protein electrophoreses, 113 subjects were available for analysis. The 95% reference interval was 6.3–20.6 mg/L for κ free light chains, 8.7–25.9 mg/L for λ free light chains and 0.46–1.23 for free light chain ratio. Most of the values fell within the manufacturer's recommended limits and therefore could be used for our population.

Serum and Urine Protein Electrophoresis and Serum-Free Light Chain Assays in the Diagnosis and Monitoring of Monoclonal Gammopathies

2020 ◽  
Vol 5 (6) ◽  
pp. 1358-1371
Author(s):  
Gurmukh Singh
Keyword(s):  
Light Chain ◽  
Protein Electrophoresis ◽  
Free Light Chain ◽  
Light Chains ◽  
Free Light Chains ◽  
Urine Protein ◽  
Serum Free ◽  
Monoclonal Gammopathies ◽  
Serum Free Light Chain ◽  
Serum Free Light Chains

Abstract Background Laboratory methods for diagnosis and monitoring of monoclonal gammopathies have evolved to include serum and urine protein electrophoresis, immunofixation electrophoresis, capillary zone electrophoresis, and immunosubtraction, serum-free light chain assay, mass spectrometry, and newly described QUIET. Content This review presents a critical appraisal of the test methods and reporting practices for the findings generated by the tests for monoclonal gammopathies. Recommendations for desirable practices to optimize test selection and provide value-added reports are presented. The shortcomings of the serum-free light chain assay are highlighted, and new assays for measuring monoclonal serum free light chains are addressed. Summary The various assays for screening, diagnosis, and monitoring of monoclonal gammopathies should be used in an algorithmic approach to avoid unnecessary testing. Reporting of the test results should be tailored to the clinical context of each individual patient to add value. Caution is urged in the interpretation of results of serum-free light chain assay, kappa/lambda ratio, and myeloma defining conditions. The distortions in serum-free light chain assay and development of oligoclonal bands in patients‘ status post hematopoietic stem cell transplants is emphasized and the need to note the location of original monoclonal Ig is stressed. The need for developing criteria that consider the differences in the biology of kappa and lambda light chain associated lesions is stressed. A new method of measuring monoclonal serum-free light chains is introduced. Reference is also made to a newly defined entity of light chain predominant intact immunoglobulin monoclonal gammopathy. The utility of urine testing in the diagnosis and monitoring of light chain only lesions is emphasized.

scholarly journals The experience of free light chains of immunoglobulin elimination in patients with monoclonal gammopathies

2019 ◽  
Vol 14 (2) ◽  
pp. 8-12
Author(s):  
E. G. Gromova ◽  
P. A. Zeynalova ◽  
N. V. Lubimova ◽  
Yu. S. Timofeev ◽  
N. E. Kushlinskiy ◽  
...  
Keyword(s):  
Renal Failure ◽  
Tumor Therapy ◽  
Light Chains ◽  
Free Light Chains ◽  
Monoclonal Gammopathies

The objective of study is to estimate the efficiency of extracorporeal free light chains of immunoglobulin elimination in patients with monoclonal gammopathies (n = 12) during hemodialysis using selective filters.Materials and methods. A blood and dialysate free light chains concentrations change was criterion of efficiency.Results and conclusion. The selective free light chains filtration give the possibility of an adequate anti-tumor therapy, could prevent the development of irreversible renal failure and hypoalbuminemia.

Strengths and weaknesses of methods for identifying monoclonal free light chains of Ig: examples from two cases with renal disease

2016 ◽  
Vol 54 (6) ◽  
Author(s):  
Stanley S. Levinson
Keyword(s):  
Renal Disease ◽  
Case Reports ◽  
Light Chains ◽  
Plasma Cell Dyscrasia ◽  
Bence Jones Protein ◽  
Free Light Chains ◽  
Serum Free ◽  
Serum Free Light Chain ◽  
Hook Effect ◽  
Immunofixation Electrophoresis

AbstractSerum free light chain (FLC) analysis with ratio and urine immunofixation electrophoresis (IFE) are both available for routine use in helping to detect plasma cell dyscrasia and related diseases.Case reports showing one serum positive for serum FLC but that showed a hook effect and overestimated the amount of monoclonal FLC while urine IFE was negative for Bence Jones protein, and a second serum that showed elevated FLC κ and λ but a normal κ/λ ratio, while urine IFE was positive for Bence Jones protein.These two techniques complement one another. Neither of the techniques is truly quantitative, and both exhibit methodological defects.

Evaluation of a new free light chain ELISA assay: bringing coherence with electrophoretic methods

2018 ◽  
Vol 56 (2) ◽  
pp. 312-322 ◽  
Author(s):  
Joannes F.M. Jacobs ◽  
Corrie M. de Kat Angelino ◽  
Huberdina M.L.M. Brouwers ◽  
Sandra A. Croockewit ◽  
Irma Joosten ◽  
...  
Keyword(s):  
Light Chain ◽  
Method Comparison ◽  
Protein Electrophoresis ◽  
Free Light Chain ◽  
Reference Ranges ◽  
Clinical Value ◽  
Serum Free Light Chain ◽  
Prognostic Stratification ◽  
Consistency Method ◽  
Assay Interference

Abstract Background: Serum free light chain (sFLC) measurements are increasingly important in the context of screening for monoclonal gammopathies, prognostic stratification, and monitoring of therapy responses. At the same time, analytical limitations have been reported with the currently available nephelometric and turbidimetric sFLC assays. We have evaluated a new quantitative sFLC ELISA for its suitability in routine clinical use. Methods: Reference ranges of the Sebia FLC assay were calculated from 208 controls. Assay interference, reproducibility, lot-to-lot variability, and linearity were assessed. Method comparison to the Freelite assay (Binding Site) was conducted by retrospective analysis of 501 patient sera. Results: Reference ranges of the Sebia κ/λFLC-ratio were 0.37–1.44. We observed good sensitivity (1.5 mg/L) and linearity in both polyclonal and monoclonal sFLC samples and never experienced antigen excess. Sebia FLC reproducibility varied between 6.7% and 8.1% with good lot-to-lot consistency. Method comparison with Freelite showed the following correlations: κFLC R=0.94, λFLC R=0.92 and κ/λFLC-ratio R=0.96. The clinical concordance of the κ/λFLC-ratio of both methods was 94%. Significant quantitative differences were observed between both methods, mainly in sera with high FLC concentrations. The Sebia monoclonal FLC concentrations were coherent with those obtained by serum protein electrophoresis (SPE). Freelite monoclonal FLC concentrations were consistently higher, with a mean 12-fold overestimation compared to SPE. Conclusions: The Sebia FLC assay provides a novel platform for sensitive and accurate sFLC measurements. The Sebia FLC showed good clinical concordance with Freelite. Further studies are warranted to confirm the clinical value of this assay.

Lambda monoclonal free light chain abnormalities detected by a serum immunofixation electrophoresis assay are underrepresented by quantitative serum free light chain results

2021 ◽  
Vol 156 (Supplement_1) ◽  
pp. S13-S14
Author(s):  
Rebecca Treger ◽  
Kathleen Hutchinson ◽  
Andrew Bryan ◽  
Chihiro Morishima
Keyword(s):  
Light Chain ◽  
Free Light Chain ◽  
Light Chains ◽  
Sample Population ◽  
Free Light Chains ◽  
Serum Free ◽  
Serum Free Light Chain ◽  
Immunofixation Electrophoresis ◽  
High Concordance ◽  
Polyclonal Antisera

Abstract Protein and immunofixation (IFIX) electrophoresis are used to diagnose and monitor monoclonal gammopathies. While IFIX detects clonal production of intact immunoglobulins and free light chains (FLC), the latter can also be quantified using a serum free light chain (SFLC) assay, in which polyclonal antisera detects epitopes specific for free kappa (KFLC) or lambda light chains (LFLC). An abnormal KFLC: LFLC ratio (KLR) serves as a surrogate for clonality. While the SFLC assay is highly sensitive, normal LFLC (<2.63mg/dL) and KLR results (>0.26 & <1.65) were found in samples with distinct lambda monoclonal free light chains visualized by IFIX (X-LMFLC). To investigate this discordance, contemporaneous SFLC or KLR values were evaluated for their ability to accurately classify monoclonal FLCs identified by IFIX. We performed a retrospective analysis of serum and urine IFIX (Sebia Hydrasys) and SFLC (Freelite®, Binding Site) results from our institution between July 2010 through December 2020, using R 4.0.2 and Tidyverse packages. From among 9,594 encounters in which a single monoclonal component was initially identified by IFIX, 157 X-LMFLC and 131 X-KMFLC samples were analyzed. Elevated LFLC with normal KFLC was identified in 105/157 X-LMFLC samples (67%), while both LFLC and KFLC were elevated in 42/157 samples (27%). Concordance between X-KMFLC and KFLC was markedly higher, where 122/131 samples (93%) displayed elevated kappa FLC (>1.94mg/dL) with normal LFLC, and only 7/131 X-KMFLC samples (5%) possessed both elevated KFLC and LFLC. The use of KLR to identify pathogenic monoclonal free light chains improved lambda concordance to 85%; however, 19/157 (12%) of X-LMFLC samples still exhibited normal KLR. High concordance of 98% was again observed for X-KMFLC with abnormal KLR. When samples were segregated according to normal or impaired renal function (eGFR > or ≤60mL/min/1.73m², respectively), this disparate identification of X-LMFLC and X-KMFLC by the SFLC assay persisted, suggesting that renal dysfunction (as measured by eGFR) does not underlie this phenomenon. Lastly, we corroborated the above findings in a larger sample population by examining patients with urine Bence Jones FLC identified by IFIX who had free or intact monoclonal components in serum (N=724), grouped by lambda or kappa light chain involvement. The cause(s) of the discrepant performance by the Freelite® SFLC assay, relative to the Sebia Hydrasys IFIX assay, for identifying lambda FLC components is currently unclear. Possible contributory factors include assay reference range cutoffs, other patient disease parameters, and differences in assay-specific polyclonal antisera. Future analyses of these factors will help to further characterize SFLC assay performance and elucidate how interpretation of composite serum FLC test results can be improved to better guide patient management.

scholarly journals Verification study of free light chains assays on reagent-optimized analysers

2019 ◽  
Vol 29 (3) ◽  
pp. 579-586
Author(s):  
Dragana Šegulja ◽  
Danica Matišić ◽  
Karmela Barišić ◽  
Dunja Rogić
Keyword(s):  
Method Comparison ◽  
Correlation Coefficients ◽  
Light Chains ◽  
Free Light Chains ◽  
Serum Samples ◽  
Three Samples ◽  
Coefficients Of Variation ◽  
Satisfactory Precision ◽  
Haematological Patients ◽  
Method Comparison Study

Introduction: Our aim was to compare analytical specifications of two assays (monoclonal vs. polyclonal) for free light chains (FLCs) quantification optimized for two different analytical platforms, nephelometer ProSpec (Siemens, Erlangen, Germany) and turbidimetric analyser Optilite (The Binding Site, Birmingham, UK). Materials and methods: The evaluation included verification of the precision, repeatability and reproducibility, estimation of accuracy and method comparison study with 37 serum samples of haematological patients. Kappa and lambda FLC were measured in each sample by both methods and kappa/lambda ratio was calculated. Results: Results show satisfactory precision of both methods with coefficients of variation for ProSpec of CVwr = 2.20% and CVbr = 3.44%, and for Optilite CVwr = 2.82% and CVbr = 4.15%. Estimated bias for FLC lambda was higher on the ProSpec analyser, but bias for FLC kappa was higher on the Optilite analyser. Correlation coefficients were 0.98; P < 0.001 for FLC kappa and 0.97; P < 0.001 for FLC lambda. Considering normal/pathological FLC ratio moderate agreement within assays was detected (κ = 0.621). When the results were categorized according to criteria for progressive disease, 4/37 (0.10) cases were differently classified. Lambda FLC values by Optilite in three samples with monoclonal FLC lambda were more than twelve times higher than by ProSpec. A 25% difference in FLC ratio was detected in 16/37 (0.43) and 50% difference in 13/37 (0.35) patients. Conclusions: All manufacturers’ precision claims could not be achieved in the verification study. The comparison of results to biological variations data showed that coefficients of variations are acceptable for both assays. The assays should not be used interchangeably in haematological patients.

scholarly journals Serum Reference Intervals and Diagnostic Ranges for Free κ and Free λ Immunoglobulin Light Chains: Relative Sensitivity for Detection of Monoclonal Light Chains

2002 ◽  
Vol 48 (9) ◽  
pp. 1437-1444 ◽  
Author(s):  
Jerry A Katzmann ◽  
Raynell J Clark ◽  
Roshini S Abraham ◽  
Sandra Bryant ◽  
James F Lymp ◽  
...  
Keyword(s):  
Light Chain ◽  
Reference Intervals ◽  
Systemic Amyloidosis ◽  
Light Chains ◽  
Light Chain Deposition Disease ◽  
Monoclonal Gammopathies ◽  
Automated Immunoassay ◽  
Light Chain Deposition ◽  
Diagnostic Intervals ◽  
Detection And Quantification

Abstract Background: The detection of monoclonal free light chains (FLCs) is an important diagnostic aid for a variety of monoclonal gammopathies and is especially important in light-chain diseases, such as light-chain myeloma, primary systemic amyloidosis, and light-chain-deposition disease. These diseases are more prevalent in the elderly, and assays to detect and quantify abnormal amounts of FLCs require reference intervals that include elderly donors. Methods: We used an automated immunoassay for FLCs and sera from a population 21–90 years of age. We used the calculated reference and diagnostic intervals to compare FLC results with those obtained by immunofixation (IFE) to detect low concentrations of monoclonal κ and λ FLCs in the sera of patients with monoclonal gammopathies. Results: Serum κ and λ FLCs increased with population age, with an apparent change for those &gt;80 years. This trend was lost when the FLC concentration was normalized to cystatin C concentration. The ratio of κ FLC to λ FLC (FLC K/L) did not exhibit an age-dependent trend. The diagnostic interval for FLC K/L was 0.26–1.65. The 95% reference interval for κ FLC was 3.3–19.4 mg/L, and that for λ FLC was 5.7–26.3 mg/L. Detection and quantification of monoclonal FLCs by nephelometry were more sensitive than IFE in serum samples from patients with primary systemic amyloidosis and light-chain-deposition disease. Conclusions: Reference and diagnostic intervals for serum FLCs have been developed for use with a new, automated immunoassay that makes the detection and quantification of monoclonal FLCs easier and more sensitive than with current methods. The serum FLC assay complements IFE and allows quantification of FLCs in light-chain-disease patients who have no detectable serum or urine M-spike.

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